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A170733
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Expansion of g.f.: (1+x)/(1-13*x).
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51
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1, 14, 182, 2366, 30758, 399854, 5198102, 67575326, 878479238, 11420230094, 148462991222, 1930018885886, 25090245516518, 326173191714734, 4240251492291542, 55123269399790046, 716602502197270598, 9315832528564517774, 121105822871338731062, 1574375697327403503806
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OFFSET
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0,2
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COMMENTS
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For n>=1, a(n) equals the numbers of words of length n-1 on alphabet {0,1,...,13} with no two adjacent letters identical. - Milan Janjic, Jan 31 2015
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LINKS
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FORMULA
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MAPLE
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k:=14; seq(`if`(n=0, 1, k*(k-1)^(n-1)), n = 0..25); # G. C. Greubel, Sep 24 2019
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MATHEMATICA
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CoefficientList[Series[(1+x)/(1-13x), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 10 2012 *)
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PROG
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(PARI) vector(26, n, k=14; if(n==1, 1, k*(k-1)^(n-2))) \\ G. C. Greubel, Sep 24 2019
(Magma) k:=14; [1] cat [k*(k-1)^(n-1): n in [1..25]]; // G. C. Greubel, Sep 24 2019
(Sage) k=14; [1]+[k*(k-1)^(n-1) for n in (1..25)] # G. C. Greubel, Sep 24 2019
(GAP) k:=14;; Concatenation([1], List([1..25], n-> k*(k-1)^(n-1) )); # G. C. Greubel, Sep 24 2019
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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